Device for applying liquid adhesive to workpieces



July 25, 1950 H. D. ELLIOTT 2,516,110

DEVICE FOR APPLYING LIQUID ADHESIVE TO WORKPIECES Filed July 25, 1947 2 Sheets-Sheet 1 Inventor Harry D. Elliott By his Aitor'ney July 25, 1950 Filed July 25, 1947 H. D. ELLIOTT 2,516,110

DEVICE FOR APPLYING LIQUID ADHESIVE TO WORKPIECES 2 Sheets-Sheet 2 Inventor Harry D Ellio'ft By his Attor ney Patented July 25, 1950 DEVIGE FOR APPLYING LIQUID ADHESIVE TO WORKPIECES Harry D. Elliott, Wenham, Mass., assignor to United Shoe Machinery Corporation, Fleming ton, N. J., a corporation of New Jersey Application July 25, 1947, Serial No. 763,561

4 Claims.

This invention relates to devices for applying liquid adhesive to Work pieces such as strips of tape for reinforcing-shoe parts. The device illustrated herein can conveniently be incorporated in a reinforcing-tape-applying machine of the type disclosed in United States Letters Patent No. 2,453,212, granted on November 9, 1948, upon an application filed in my name and of which the present application is a continuation-in-part.

The adhesive commonly used in such machines is solid at room temperatures and is maintained in workable fluid condition by heating units such as electrical resistance coils. The illustrated de-- vice comprises an applicator whichis raised from beneath the surface of a liquid adhesive contained in a receptacle into contactwith the under surface of a, work piece supported above the liquid adhesive and it includes also a pump for supplying liquid adhesive to the receptacle. Inasmuch as the applicator and the movable element of the pump must perform their movements in contact with the adhesive, it is evident that the operation of these movable members is dependent upon the fluidity of the adhesive and that, in the absence of some provision to the contrary, a congealing of the adhesive during operation of the device or an attempt to start the operation of the device after the adhesive has congealed might result in breakage of the movable members or their operating mechanism.

It is an object of the present invention to provide an adhesive applying device which is not subject to breakage by reason of attempted operation while the adhesive is in a congealed state. In accordance with a feature of the invention, the illustrated device includes, in its mechanism for operating the applicator and the pump, an element which can yield to avoid breakagewhen movement of any part of the device is prevented by the congealed adhesive. As shown herein, the operating mechanism of the device includes a lever composed of two arms normally held in predetermined angular relation by a spring, one of the arms carrying a cam roll which is held in contact with its operating cam by another spring. Rotation of the cam can take place when the liquid :is congealed, in which case either the first mentioned spring will yield to enable the cam roll to be moved'radiall outward by the cam or the second mentioned spring will remain stretched to enable the cam roll to remain off the periphery of the depressed portion of the cam.

These and other features of the invention, including various details of construction and combinations of parts, will be more particularly de- 2 scribed by reference to the accompanying drawlugs and pointed out in the claims.

In the drawings,

Fig. 1 is a plan view of an illustrative machine embodying the invention; s

Fig. 2 is a vertical section of the machine taken on the line IIII of Fig. l;

Fig. 3 is a vertical section taken on the line III-III of Fig. 1; and

Fig. 4 is a vertical section taken on the line IVIV of Fig. 1.

Many of the parts of the machine herein illustrated are similar to parts of the machine disclosed in Letters Patent No. 2,453,212, above men'- tioned, and are identified herein, for convenience, by the same reference characters as are used to identify corresponding parts in said Letters Patent.

The tape engaging instrumentalities of the illustrated machine include an upper feed roll l0 (Fig. 3) and a lower feed roll l2 cooperatingtherewith to feed a predetermined length of tape T transversely of the machine, a horizontal wire [4 for supporting the tape thus fed above a receptacle l6 which contains a liquid adhesive, an applicator [8 (Fig. 2) for raising a quantity of adhesive from the receptacle and applying it to the under surface of the supported tape, and a pair of cutting blades 20 and 22 for severing the length of tape. The machine is further provided with a work table 24 for supporting a shoe part (not shown) to which the adhesively coated and severed length of tape is moved by a transfer mechanism 26 from its position on the wire Hi to a forward position on the shoe part. The tape in its passage to the feed rolls Iii and i2 is drawn from a reel and through a guide, neither of which is shown herein.

The supporting structure of the machine comprises a rigid housing 36 adapted to be secured upon a Work bench. A cover 48 (Fig. 1) is pro vided for such portions of the driving mechanism as would otherwise be exposed.

The feed rolls l0 and 12, the transfer mechanism '26, and the applicator it are all driven by mechanism operated by a countershaft 32 (Fig: 1) which is driven through a gear 8d and a pinion 86 from a drive shaft 88. An automatically disengaging clutch 90, including a cam 92, 'cou-'- ples a pulley 94 to the drive shaft 88 to cause the machine to be driven through a single cycle of operations. The pulley 94 is driven through a belt 96 from a pulley 98 mounted upon the shaft of amotor I00.

The receptacle I6 is supported upon a heated block I08 (Fig. 3) mounted within the housing 36 and is supplied with a thermoactive adhesive, liquid when hot and solid when cold, from a container I I by means which will be described later. The tape supporting Wire I4 is secured to the receptacle I6 by screws I I2. The applicator I6 comprises a bar extending lengthwise of the container (i. e., transversely of the machine) and having a horizontal top edge I'I4 (Fig. 1) which, when the applicator is raised out of the adhesive within the receptacle I6, comes into contact with the under surface of the supported tape and thus applies adhesive to the tape while the tape is held down on the wire I4 by the transfer device 26. The applicator I8 is integral with a bracket II6 which, in plan view (Fig. 1), is rectangular with a rectangular central opening Ill, and which, in side elevation (Fig. 2), is seen to bend down below the surface of the liquid adhesive in the receptacle I6, then forward, and. then up to the ends of the applicator I8 which constitutes the forward portion of the bracket II 6. The bracket II6 has a rearwardly extending shank '8 by which it is mounted upon a lever I20. A pair of screws I22, extending through slots in the shank II8 which permit forward and rearward adjustment, secure the shank I I 8 to the lever I20. A stop screw I24 (Figs. 1 and 3), threaded downwardly through a lug I26 extending from a stationary portion of the machine, engages the shank II8 to limit the upward movement of the applicator. The lever I20 has a hub I28 (Fig. by which the lever is pivotally mounted upon a stationary shaft I30. A post I32 (Fig. 2) rising from the base plate of the housing 36 supports one end of the shaft I30, and a boss I34 on the right-hand side wall of the housing supports the other end of the shaft. The shaft I30 is also utilized to support the housing 48.

The mechanism for operating the applicator I8 comprises a lever I36 having a hub I38 which is freely rotatable upon the shaft I30. Carried upon the free end of the lever I36 is a cam roll I40 engageable with a cam I42 secured upon the countershaft 82. A spring I44 secured at its upper end to the lever I36, and anchored at its lower end to a hook I46 secured in the housing 36, normally holds the roll I40 in engagement with the cam. Formed upon the lever I36 is a lug I48 engageable with a lug I50 extending laterally from the lever I20. A tension spring I52 connected at its ends to the levers I20 and I36, respectively, normally holds the lugs I48 and I50 in engagement with each other. The construction just described serves to prevent danger of breakage when the adhesive, liquid only while hot, is congealed in the receptacle I6. For example, if the applicator I8, while in its lowermost position as shown in Fig. 2, is embedded in a mass of congealed liquid, the rotation of the cam I42 will bring the low portion of the cam beneath the roll I40, but will not cause breakage because the spring I44 will exert its force yieldingly upon the lever I36 without bringing the cam roll into engagement with the low portion of the cam. If, on the other hand, the applicator I8 should be in its uppermost position above a mass of congealed adhesive, the rotation of the cam I42, while positively forcing the lever I36 up, will not forcibly move the lever I20 because the spring I'52 will yield and permit the lugs I48 and I50 to separate.

The various parts of the illustrated machine, as so far described, are similar in construction and mode of operation to like numbered parts 4 of the machine disclosed in Letters Patent No. 2,453, 212, above mentioned.

The machine shown herein is further provided with means, now to be described, for maintaining a supply of liquid adhesive at a constant level within the receptacle I6. The container I I0 from which the adhesive is supplied comprises a reservoir 500 which receives the adhesive from an inverted carton 502 mounted directly above it and supported upon a wire 504 extending diametrically across the reservoir 500. A cover 506 fits over the carton 502 when the latter is thus positioned over the reservoir 500. The adhesive, which is initially solid in the carton 502, is melted by a heating device, later to be described, and drops into the reservoir 500 wherein it is maintained in liquid condition. The carton 502 may conveniently be the same pasteboard container in which the adhesive is purchased.

The receptacle I6 and the reservoir 500 are integral, being parts of a single casting, and they are joined by a neck which is channel shaped in cross section and which has a pair of side walls 508 (Figs. 1 and 3) and a thick base 5I0 (Fig. 3) having its upper surface above the highest level to which liquid adhesive will be supplied to the reservoir 500. This neck extends from a lug 5I2 formed on the side of the reservoir 500. The channel formed by the walls 508 and the base 5I0 communicates at one end with the interior of the receptacle I6 and at its opposite end with the interior of the reservoir 500. It thus serves as a passageway for excess liquid adhesive in the receptacle I6 to flow back into the reservoir 500.

Extending heightwise through the lug 5I2 is a bore 5I4 (Figs. 2 and 4) which serves as a cylinder for a pump plunger 5I6. Disposed horizontally in the lug 5I2 and providing communication'between the bore 5I4 and the interior of the reservoir 500 is a bore 5I8 which serves as an inlet duct to the pump. Extending down into the lug 5I2 parallel to the bore 5I4 is a bore 520 which serves as a valve chamber. Continuing down through the lug 5I2 is a bore 522 coaxial with the bore 520 and of smaller diameter, leaving a shoulder at the junction of the bores 522 and 520 which forms a seat for a ball valve 526. Formed in the under surface of the lug 5I2 and connecting the lower ends of the bores 5I4 and. 522 is a groove 528. A cover plate 530 secured to the under surface of the lug 5I2 covers the groove 528 to form a duct leading from the bore or pump cylinder 5| 4 to the bore 522 or valve entrance. The plate 530 covers also the lower ends of the bores 5I4 and 522. The pump inlet duct'5I8 enters the pump cylinder 5I4 at a level slightly higher than the level at which the groove 528, which is the pump outlet duct, leaves the pump cylinder.

Extending horizontally lengthwise through the thick base 5I0 of the neck 508 is a duct 532 com-' municating with the upper portion of the valve chamber 520 and constituting the valve outlet duct. Leading up from the duct 532 and opening into the interior of the receptacle I6 is an inclined passage 534 which is a continuation of the duct 532.

The pump plunger 5 I 6 has an integral upwardly extending stem 536 (Fig. 2), the upper end of which carries a pair of rotatable horizontal coaxial pins 538 (Fig. l). The outer end portions of these pins 538 are in the form of slide blocks which engage slots provided in a pair of ears extending from a crank arm 540 which is mounted upon one end portion :of a shaft 542. The opposite *end portion :of the shaft 542 carries a gear segment 5% (Fig. 2) which meshes with and .is driven by a gear segment 545 on the lever I211. The shaft 542 isjournaled in a bearing 548 (Fig. 3) which is integral with a cover 550 secured upon the upper edge of the casting Which forms the receptacle l'fi and :the reservoir 505. The lug I26, previously mentioned, is integral with the bearing 5418;. The cover :5510 covers the passageway :formed bythe side walls-508 and the base 51 i), and it also has .a ring shaped portion extending over :the reservoir :5U0ifor receiving the carton 502 and supporting the cover 506. A groove 552 formed in the upper surface of the lug 5I2 connects the upper portion-of the pump cylinder 5! with the passage between the walls 58 to permit the escape of air from the pump cylinder as the plunger 5J6 rises. The cover 550 covers the groove 552 and the top of the pumpcylinder 5M,

having a bearing hole through which the stem 536 reciprocates.

The level of the liquid adhesive within the receptacle is determined by an overflow weir 554 extending-across the passageway between the Walls 508. 'The weir554consists of a bent up edge portion of a plate 556 which is secured upon the base 510, the top edge of the weir being within the reservoir 50!] to enable surplus adhesive from the receptacle I6 to drip down into the mass of adhesive within the reservoir. The plate 555 serves also to close the upper end of the valve chamber 520.

The adhesive within the receptacle is maintained in a fluid state by an electrical resistance heating unit 558 which fits within a horizontal bore in the block H18. The adhesive Within the reservoir is maintained in a liquid state, and the solid adhesive within the carton 502 is melted, by an electrical resistance heating unit 550 which fits within heightwise coaxial bores in the cover 550 and the lug 5l2. An opening 562 in the cover 550 directly over the weir 554 enables the operator to observe conditions within the reservoir 500. A guard 564- secured to the reservoir 500 and spaced therefrom protects the operators hands from accidental contact with the heated reser- The operation of the above described instrumentalities for supplying adhesive from the reservoir 500 to the receptacle I5 is effected by movements of the lever l2!) acting, through the gear segments 546 and 544, the shaft 542, and the crank arm 54!], to reciprocate the plunger 5I6 in unison with the applicator l8. Upward mover ment of the plunger 5| 6 effects a partial vacuum in the pump cylinder 5M below the plunger and also in the groove 528 and the bore 522 which holds the valve 526 upon its seat. As soon as the plunger rises high enough to uncover the opening of the inlet duct 5l8, liquid adhesive flows from this duct into the pump cylinder to relieve this vacuum. Descent of the plunger 5|6 first closes the opening of the duct 5l8 and prevents the liquid in the pump cylinder from escaping back through the duct 518 into the reservoir 560, and continued descent of the plunger forces the liquid trapped in the pump cylinder, the groove 528, and the bore 522 up past the valve 526 into the valve chamber 52 and thence through the duct 532 and the passage 534 into the receptacle it.

The diameter of the pump cylinder 5M and the length of the stroke of the plunger 516 are both slight and the quantity of adhesive delivered by each stroke of the pump is not more than a few to apply some of the liquid adhesive to the work a plied to the tape T with each upward stroke of the applicator I8 is slightly less than-the quantity delivered to the receptacle It with each downward stroke of the plunger 515, and the :excess flows over the Weir 554 into the reservoir 500; v

If for an reason the heating system should fail during operation and the adhesive should congeal, or if rotation of the shaft 82 should inadvertently be started before the adhesive has melted, no breakage will take place by reason of the plunger 586 being held stationary by the congealed adhesive. In such case the spring 152 would yield Without forcing the plunger down,

and the spring 144 would remain stretched Without forcing theplunger up. These springs thus serve as yielding elements in the plunger operating means as well as in the applicator operating means. I

Having described my invention, What I claim as new and desire to secure by Letters Patent of the United States is: i

1. In adevice for applying a congealable liquid adhesive to a work piece, a receptacle for said liquid adhesive, means movable through said liquid adhesive for applying the liquid adhesive to the work piece, a pump for supplying liquid adhesive to the receptacle, a common means for operating said applying means and said pump, adjacent members having abutting surfaces and included in said common operating means, and a spring normally holding said surfaces together to render the members effective to transmit movement from one to the other, said sprin being yieldable in response to excessive resistance offered by the adhesive to the operation of the appying means and the pump, said spring serving thereby to avoid breakage by reason of a congealing of the liquid adhesive.

2. In a device for applying a, congealable liquid adhesive to a work piece, a receptacle for said liquid adhesive, said receptacle having an overflow weir, a pump for supplying liquid adhesive to said receptacle to maintain the surface of the liquid adhesive in the receptacle at a constant level determined by said overflow weir, an applicator adapted to be raised from below the surface of the liquid adhesive in the receptacle into contact with a work piece above said surface to cause the applicator to apply some of the liquid adhesive to the work piece, a common means for operating said pump and said applicator, a pair of movement-transmitting members being included in said common operating means, said movement-transmitting members being mounted for movement in overlapping paths and having abutting surfaces, and a spring normally holding said surfaces in contact to render the members effective to operate the pump and the applicator, said spring being yieldable in response to excessive resistance offered by the adhesive to the operation of the applicator and the pump, said spring serving thereby to avoid breakage by reason of a congealing of the liquid adhesive.

3. In a device for applying a congealable liquid adhesive to a work piece, a receptacle for said liquid adhesive, an applicator adapted to be raised from below the surface of the liquid adhesive in the receptacle into contact with a work piece above said surface to cause the applicator Although the plunger 5.1.6 in its upward piece, a, reciprocating pump having a plunger movable heightwise in a cylinder for supplying liquid adhesive to said receptacle, 9, common operating member connected to said applicator and said plunger, and means for raising and lowering said operatin member to operate the applicator and the pump in unison.

4. In a device for applying a congealable liquid adhesive to a work piece, a receptacle for said liquid adhesive, means for supporting the work piece above the liquid adhesive in said receptacle, an applicator adapted to be raised from below the surface of the liquid adhesive in the receptacle into contact with the under surface of the work piece to apply some of the liquid adhesive to the work piece, a lever upon which said applicator is mounted, a fulcrum about which said lever swings to effect heightwise movement of the applicator, a second lever pivotally mounted on said fulcrum mutually engageable stops on said levers through which the second lever can positively swing the first lever about said fulcrum in one direction, a spring having its ends secured respectively to the levers and through which the second lever can yieldably swing the 25 first lever about said fulcrum in the opposite direction, a, movable cam, a cam follower on the second lever engageable with said cam, said cam being arranged to swing the second lever and thereby the first lever in the second-mentioned direction, and a spring acting yieldingly upon the second lever and thence, through the stops, upon the first lever to swing the first lever in the first-mentioned direction against the cam, the purpose of the first spring being to prevent breakage which might result from the positive thrust of the cam against the cam follower when the adhesive is congealed, and the purpose of the second spring being to hold the cam follower yieldably against the cam and thereby to prevent breakage when the adhesive is congealed.

HARRY D. ELLIOTT.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,192,380 Brackett July 25, 1916 2,129,828 Dunn Sept. 13, 1938 2,293,692 Wylie Aug. 18, 1942 

